1. Field of the Invention
The invention relates to a speaker supporter supporting a speaker diaphragm and a magnetic circuit and to a speaker unit including the speaker supporter.
2. Description of the Background Art
FIG. 1 shows a sectional view of a structure of a speaker unit. A speaker unit 1 includes a vibrating part, a speaker supporter, and a magnetic circuit part. The vibrating part has a diaphragm 11, a voice coil 12, a voice coil bobbin 13, and a damper 14.
The diaphragm 11 vibrates in response to an electrical signal input to the voice coil 12, which emits a sound corresponding to the input signal. The diaphragm 11 is made of pulp, resin, or other materials. The center part of the diaphragm 11 is attached and secured to one end of the cylinder of the voice coil bobbin 13. The opening part of the diaphragm 11 is attached and secured to an edge part 15. The outer circumference part of the edge part 15 is attached and secured to a speaker supporter 20.
The outer circumference of the voice coil bobbin 13 securing the diaphragm 11 is attached to the inner circumference of the damper 14. The outer circumference of the damper 14 is attached to the speaker supporter 20. Therefore, the diaphragm 11 is attached and secured to the edge part 15 and damper 14 in a hanging state.
The voice coil bobbin 13 is made of a light member such as paper, resin, or aluminum formed into a cylindrical shape. An insulated copper or aluminum thin wire is coiled on the outer circumference of the cylindrical shape, which forms the voice coil 12. The damper 14, made of resin or blended fabric, supports the diaphragm 11 so that the diaphragm 11 can move in response to the vibrations of the voice coil bobbin 13.
The magnetic circuit part has a ring permanent magnet 30 (hereafter, abbreviated to as a magnet 30), a bottom yoke 31, and a top plate 32. In the magnetic circuit part, the bottom yoke 31 and the top plate 32 are attached to both end faces of the magnet 30 for securing.
The bottom yoke 31 has a center pole 33 having a cylindrical shape and a flange part 34 having a spread shape at one end face of the center pole 33. On the bottom yoke 31 made of magnetic carbon steel or the like, a protective coating against corrosion is applied after shaping by cutting process or the like. The shape of the top plate 32 is a washer. On the top plate 32 made of magnetic rolled steel plate or the like, a protective coating against corrosion is applied after shaping such as press working.
The speaker supporter 20 is a member supporting the magnetic circuit part and the vibrating part. The vibrating part is secured inside the speaker supporter 20. The magnetic circuit part is secured at the rear portion (right side in FIG. 1) of the speaker supporter 20. The speaker supporter 20 is made of resin or other materials.
As shown by an arrow 90, in the specification, “forward” or “front side” of a speaker or the speaker unit 1 refers to the side where the diaphragm 11 is installed (left side in FIG. 1) in terms of the speaker unit 1. As well, “Backward” or “rear side” of the speaker or the speaker unit 1 refers to the side where the magnetic circuit part is installed (right side in FIG. 1) in terms of the speaker unit 1.
FIG. 2 shows a rear view of the speaker supporter 20. FIG. 3 shows a perspective view of the speaker supporter 20. The speaker supporter 20 has a frame 21, a retainer 22, a leg 23a, a leg 23b, a leg 23c, a leg 23d, a leg 23e, and a leg 23f. Hereafter, the legs 23a to 23f may be described collectively as “legs 23” (or “leg 23” for one of the legs 23) without suffixes of “a,” “b” or others.
The frame 21 secures the edge part 15 attached and secured to the outer circumference of the diaphragm 11. That is, the outer circumference of the diaphragm 11 is secured to the frame 21 through the edge part 15. The retainer 22 supports the magnetic circuit part. Six of the legs 23a to 23f extend from the inner wall of the frame 21 in the vicinity of the front of the speaker, and connect to the retainer 22. This secures the retainer 22 to the frame 21.
An attaching surface 24 is formed on the outside wall of the frame 21. The speaker unit 1 is installed with the attaching surface 24 screwed to the mounting surface of the intended installation position.
Another structure is proposed for the case where a flange part is formed at the end part of a frame, and a speaker unit is installed at the outer peripheral of an installation hole on the installation position. One end of the flange part has an engaging part to engage with the installation position through the installation hole and another end of the flange part has an auxiliary member for installation having elastic characteristics to be locked at the installation position through the installation hole.
Conventionally, the mass of a speaker unit is reduced by the use of a downsized magnetic circuit part or lighter material for a frame or legs.